/**
 * @file: graph.cpp
 * Graph class implementation
 */
/*
 * Graph library, internal representation of graphs in ShowGraph tool.
 * Copyright (c) 2009, Boris Shurygin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "graph_iface.h"

/**
 * Constructor.
 */
Graph::Graph( bool create_pools):
    node_next_id( 0),
    edge_next_id( 0),
    node_num( 0),
    edge_num( 0),
    first_node( NULL),
    first_edge( NULL),
    node_pool( NULL),
    edge_pool( NULL)
{
    QDomElement root = createElement("graph");
    appendChild( root);
    if ( create_pools)
        createPools();
}

/**
 * Destructor - removes all nodes
 */
Graph::~Graph()
{
    for ( Node *node = firstNode();
          isNotNullP( node);
          )
    {
        Node* next = node->nextNode();
        deleteNode( node);
        node = next;
    }
    destroyPools();
}

/** Pools' creation routine */
void Graph::createPools()
{
    node_pool = new FixedPool< Node>();
    edge_pool = new FixedPool< Edge>();
}

/** Pools' destruction routine */
void Graph::destroyPools()
{
    delete node_pool;
    delete edge_pool;
}

/**
 * Build graph from XML description
 */
void
Graph::readFromXML( QString filename)
{
    QFile file( filename);

    if ( !file.open( QIODevice::ReadOnly))
        return;

    if ( !setContent( &file))
    {
        GRAPH_ASSERTD( 0, "Not a good-formated xml file");
        file.close();
        return;
    }
    file.close();

    /**
     * Read nodes and create them
     */
    QDomElement docElem = documentElement();

    QDomNode n = docElem.firstChild();
    QHash< GraphUid, Node *> n_hash;

    while ( !n.isNull())
    {
        QDomElement e = n.toElement(); // try to convert the DOM tree node to an element.
        
        if ( !e.isNull() && e.tagName() == QString( "node"))
        {
            Node *node = newNode( e);
            node->readFromElement( e);
            n_hash[ e.attribute( "id").toLongLong()] = node;
        }
        n = n.nextSibling();
    }
    
    n = docElem.firstChild();
    while ( !n.isNull())
    {
        QDomElement e = n.toElement(); // try to convert the DOM tree node to an element.
        
        if ( !e.isNull() && e.tagName() == QString( "edge"))
        {
            GraphUid pred_id = e.attribute( "source").toLongLong();
            GraphUid succ_id = e.attribute( "target").toLongLong();
            Node *pred = n_hash[ pred_id];
            Node *succ = n_hash[ succ_id];
            Edge *edge = newEdge( pred, succ, e);
            edge->readFromElement( e);
        }
        n = n.nextSibling();
    }
}

/** Node/Edge creation routines can be overloaded by derived class */
Node * 
Graph::createNode( int _id)
{
    return new ( node_pool) Node ( this, _id);
}

Edge * 
Graph::createEdge( int _id, Node *_pred, Node* _succ)
{
    return new ( edge_pool) Edge( this, _id, _pred, _succ);
}

/**
 * Print graph to stdout in DOT format.
 * Note: Iterates through nodes and edges separately instead
 *       of iterating through nodes and at iterating through edges of each node
 */
void 
Graph::debugPrint()
{
    Node *n;
    Edge *e;
    out( "digraph{");
    /** Print nodes */
    for (  n = firstNode(); isNotNullP( n); n = n->nextNode())
    {
        n->debugPrint();
    }
    /** Print edges */
    for (  e = firstEdge(); isNotNullP( e); e = e->nextEdge())
    {
        e->debugPrint();
    }
    out( "}");
}

/**
 * Implementation for numerations cleanup
 */
void 
Graph::clearNumerationsInObjects()
{
    Node *n;
    Edge *e;
    /** Clean markers in nodes */
    for ( n = firstNode(); isNotNullP( n); n = n->nextNode())
    {
        clearUnusedNumerations( n);
    }
    /** Clean markers in edges */
    for ( e = firstEdge(); isNotNullP( e); e = e->nextEdge())
    {
        clearUnusedNumerations( e);
    }
}

/**
 * Implementation for markers cleanup
 */
void 
Graph::clearMarkersInObjects()
{
    Node *n;
    Edge *e;
    /** Clean markers in nodes */
    for (  n = firstNode(); isNotNullP( n); n = n->nextNode())
    {
        clearUnusedMarkers( static_cast<Marked *>(n));
    }
    /** Clean markers in edges */
    for (  e = firstEdge(); isNotNullP( e); e = e->nextEdge())
    {
        clearUnusedMarkers( static_cast<Marked *>(n));
    }
}

/**
 * Implementation of XML writing
 */
void 
Graph::writeToXML( QString filename)
{
    QFile file( filename);
    if (!file.open(QFile::WriteOnly | QFile::Text))
    {
        assert( 0);
        return;
    }
     
    /** Update element for each node */
    for ( Node *n = firstNode(); isNotNullP( n); n = n->nextNode())
    {
        n->updateElement();
    }

    /** Update element for each edge */
    for ( Edge *e = firstEdge(); isNotNullP( e); e = e->nextEdge())
    {
        e->updateElement();
    }

    QTextStream out( &file);
    save(out, IndentSize);
}